title: A conduction block in sciatic nerves can be detected by magnetic motor root stimulation.
abstract: Useful diagnostic techniques for the acute phase of sciatic nerve palsy, an entrapment neuropathy, are not well established. The aim of this paper is to demonstrate the diagnostic utility of magnetic sacral motor root stimulation for sciatic nerve palsy. We analyzed the peripheral nerves innervating the abductor hallucis muscle using both electrical stimulations at the ankle and knee and magnetic stimulations at the neuro-foramina and conus medullaris levels in a patient with sciatic nerve palsy at the level of the piriformis muscle due to gluteal compression related to alcohol consumption. On the fourth day after onset, magnetic sacral motor root stimulation using a MATS coil (the MATS coil stimulation method) clearly revealed a conduction block between the knee and the sacral neuro-foramina. Two weeks after onset, needle electromyography supported the existence of the focal lesion. The MATS coil stimulation method clearly revealed a conduction block in the sciatic nerve and is therefore a useful diagnostic tool for the abnormal neurophysiological findings associated with sciatic nerve palsy even at the acute phase.
authors.affiliation: Department of Neurology, Japanese Red Cross Medical Center, Tokyo, Japan. hideyukimatsumoto.jp@gmail.com
authors.forename: Hideyuki
authors.initials: H
authors.lastname: Matsumoto
authors.forename: Yuko
authors.initials: Y
authors.lastname: Konoma
authors.forename: Kengo
authors.initials: K
authors.lastname: Fujii
authors.forename: Ritsuko
authors.initials: R
authors.lastname: Hanajima
authors.forename: Yasuo
authors.initials: Y
authors.lastname: Terao
authors.forename: Yoshikazu
authors.initials: Y
authors.lastname: Ugawa
mesh_terms: D000200:Action Potentials / Q000502:physiology; D000328:Adult; D004558:Electric Stimulation; D004576:Electromyography; D006801:Humans; D008280:Magnetics; D008297:Male; D009431:Neural Conduction / Q000502:physiology*; D020426:Sciatic Neuropathy / Q000175:diagnosis* / Q000503:physiopathology*
keywords: Compound muscle action potential; Conduction block; Magnetic stimulation; Piriformis syndrome; Sciatic nerve palsy; Supramaximal stimulation